The present invention is related to computer systems and in particular to a floppy disk drive that functions as both an internal and external disk drive.
Until recently, software for personal computers was distributed on floppy disks, usually 3.5xe2x80x3 floppies. Now, however, as the price of CD ROM technology has decreased and the size of program code has increased, a majority of software companies are moving to higher data density CD ROM""s as the preferred distribution media. Despite the increased use of CD ROM""s by software vendors, many computer users still prefer a floppy disk for such tasks as loading small programs, exchanging data with other users, and backing up critical files. Therefore, computer manufacturers continue to offer floppy disk drives as either standard or optional equipment on computer systems. In the case of portable computers, including both a floppy drive and a CD ROM drive poses difficult choices for the manufacturer and the user due to the limited space available in the portable computer case and the need to make the portable computer as light as possible.
If the portable computer has a built-in floppy drive, little or no room is left to include a CD ROM drive. If the CD ROM drive is built-in and the floppy drive is offered as an external option, the user must carry the floppy drive and its cabling along with the computer when traveling. A recently introduced alternative allows the user to interchange a removable CD ROM drive and a removable floppy disk drive in the same computer bay. One drawback with this last approach is that the normally small floppy disk drive must be enclosed in a casing that conforms to the CD ROM form factor size and mechanical requirements. Therefore, if a user wishes to have both CD ROM and floppy disk capabilities while traveling, one of the large drives must be carried externally. An additional drawback is that only one of the drives may be used at any one time. One way to eliminate these drawbacks is to also purchase a portable external drive to be used when both floppies and CD ROM""s are needed simultaneously. However, if the user does not want to spend the additional money to have both removable and portable floppy disk drives, then the user must decide between the portable external floppy drive or the removable floppy drive. This decision is based in part on predicting how frequently the user will need the floppy drive over the life of the computer and is thus often regretted as the user""s needs change.
For the manufacturer, the current solutions to the problem of providing internal and external floppy disk drives with portable computers require it to maintain two separate floppy disk drive units in inventory, one for internal use and one for external use, resulting in higher inventory costs.
A modular 3.5xe2x80x3 floppy disk drive (FDD) is externally attachable to a computer and, when combined with an appropriate form factor carrier, is insertable into a computer peripheral option bay configured for other types of removable drives so that it functions as an internal drive.
A standard FDD unit is enclosed in a modular shell suitable for external use. The FDD unit has data/control lines coupled to an electrical connector fixed in the shell. The electrical connector is designated as a shell adaptor connector. A cable couples to the shell adaptor connector to attach the modular FDD to the computer through either a proprietary or standard interface, such as a parallel port or PCMCIA slot, when the modular FDD is being used externally.
For internal use, the modular FDD is inserted into a carrier that acts as a form factor adaptor to make the modular FDD compatible with the size and mechanical requirements of a computer peripheral option bay configured for a removable CD ROM drive. When the modular FDD is inserted into the carrier, the shell adaptor connector couples to a corresponding electrical connector on the inside of the carrier. Another electrical connector is molded into the outside of the carrier and has the physical configuration of a connector on the removable CD ROM drive. The inside and outside electrical connectors are coupled together so that the FDD data/control signals are routed from the inside electrical connector to the appropriate electrical contacts of the outside electrical connector and complete an electrical connection between the FDD unit and the computer when the carrier holding the modular FDD is inserted into the peripheral option bay. The computer determines the type of device inserted into the peripheral option bay by reading signals sent by the device on certain of its data/control lines.
The carrier itself is substantially U-shaped in cross-section with the modular FDD fitting into an open-mouthed slot formed between the legs of the U. In an alternate embodiment, latching tabs at the open end of the slot exert tension on the modular FDD to hold it in the carrier. The latching tabs have different shapes and grooves on the outside of the legs of the shell are keyed to the tabs so that the modular FDD can be inserted into the carrier in only one orientation.
In one embodiment, the shell adaptor connector is a shrouded DB25 male connector and the inside electrical connector is a DB25 female connector. Because the DB25 connectors can be coupled in only one orientation, their use forces the user to insert the drive into the carrier correctly. The shroud of the DB25 male connector fitting around the DB25 female connector also aids in achieving a firm electrical connection between the modular FDD and the carrier.
In still another alternate embodiment, a good electrical connection between the modular FDD and the carrier is ensured by recessing the inside electrical connector into the carrier so that the shell adaptor connector fits tightly into the recess and is unlikely to work loose when coupled to the inside electrical connector.
A circuit to reduce electromagnetic interference is disclosed in another embodiment. An electrical grounding contact is molded into the modular shell which is coupled to a corresponding grounding point on the FDD unit. A metal plate is attached to the carrier and makes contact with the grounding contact when the modular FDD is inserted into the carrier. The metal plate is grounded to the computer chassis when the carrier is inserted into the computer bay.
In still other embodiments, the modular FDD is used as an external device by coupling one end of a cable to the shell adaptor connector on the modular FDD. The opposite end of the cable is terminated with a connector, such as a PCMCIA card connector or a standard parallel port connector, which is further coupled to the appropriate interface on the computer. A further alternate embodiment comprises a substantially L-shaped carrier having the same electrical connections as the substantially U-shaped carrier.
The ability to interface a single modular FDD to a computer both internally and externally saves the user money by combining two functions into one unit. A standard FDD unit is surrounded by a shell to protect it from damage when being used externally. Because the carrier acts as a form factor adaptor, the carrier provides the size and mechanical interfaces required by the peripheral option bay when the modular FDD is being used internally. Therefore, the shell surrounding the FDD unit can be almost as small as the FDD unit, making it very portable and easy to carry when the user is on the road and needs the peripheral option bay for other devices while still having access to floppies. Alternatively, if the user will not need the CD ROM drive while on the road, the modular FDD and carrier combination can be inserted into the computer bay, giving the user maximum portability. Furthermore, because the modular FDD operates either internally or externally, the user does not have to purchase two separate units to get both functions, nor decide in advance how frequently the FDD will be used over several years. Finally, since the modular FDD is usable without the carrier, the carrier can be made a separately purchased item thereby giving the user the option of upgrading to internal use later, and allowing the manufacturer to reduce its inventory to a single type of FDD.